Telephone system



June '12, 192s.

G. THOMPSON TELEPHONE SYSTEM Arm/Mfr G. THOMPSON TELEPHONE SYSTEM June 12, 1928.

6 Sheets-Shes Filed Jung 12, ma n 1,672,994" G. THOMPSON TELEPHONE s YsTEM l Filed March-26, s snee` RELAY CML /No/cATa/w /MPaLsE .5w/rch' F/GJ,

5y f6 Mr Arm/Mfr June l2, 1928.

, y 1,672,994 G. THOMPSON' TELEPHONE SYSTEM l www .s

Filed March 26, 1927 June 12, 192s.

G. THOMPSON TELEPHONE SYSTEM- Filed March 26l 927 Arrow/Ey June 12, 192s. 1,612,994

G. THOMPSO N TELEPHONE SYSTEM Filed .March 26, 1927 6 Sheets-Sheet 6 Patented y J une 12,

UNITED "STATES PATENT WFICII.y

NEW YORK, ASSIGNOR To WESTERN" ELEC- GEORGE THOMPSON, OF MOUNT VERNON,

TRIC COMPANY, INCORPORATED, OF NEW YORK.

YORK, N. Y., CORPORATION `01E" NEXT1 TELEPHONE- sYs'rEiiL o Application med March 2s, 19727,` "serial No. 178,551,"

This inventionl relatestosignaling sys` tems and more particularly to machine switching telephone exchange systems and has for' an object theprovision ofimproved means for establishing telephonie` connec` ers or similar Adriving apparatus and that the position assumed by such switchesis controlled. by means of impulses sent from` the switch to a control device or sender.

i Automatic switches of the step-byfstep type are directly operated by means of amagnet or magnets, `the circuit of which is Controlled by impulses normally transmitted from lthe subscribers substation. Where offices e1nployingboth types saine exchange area, the interconnectionof such offices requires that the equipment `be capable ot adaptation to control the partie! ular type of apparatus to which theconr nection is to be extended.

`In accordance with the present`y invention the control-device atan oice` employing power driven switches is characterized in.

this that it is'equippedwith means `for receiving pulses from power driven switches and for transmitting pulses to stepp-b'y-step switches; that means are provided i'ior determining the number of impulses in each case andy the Vcontrol ,device discriminates between these means in accordance with the v designationof the called oliiceythatthe imextended tostep-by-step switchesto pulse transmitting means hasta plurality of normal positions" and the number determining means is preferably so associated therewith as `to have the same numerical significance irrespective of the normal position from which this impulse transmitting means starts;` and that a `timing arrangement/is provided jwhich is effective wherea callis allow for the trunk hunting operation by` these switches and this timing means is `so ar ranged that: the duration of the interval measured. may be varied at will. l 1

The invention tinds embodiment ina reg' of switches exist in the ister sender` forming a partof a power driv`` en system. The initiation of a call bya subscriber causes thel associationot'a lcall-. ing linewith a district selector and through a' sender selector with a sender. The operation ol'f the subscribers dial results in the registration of the number of the wanted subscriber in the sender. In response to the dialing ofthe digits forming the code of the ohce in whichthe called subscriber is located, the code registersare positioned and a translator is set' therefromto control the selectiono an outgoing trunk to that olice.` TheL translator positions a class switch,V which controls the operation of the sender 1n accordance with the nature of `that ottica In the establishment of a connection "to an outgoing trunk,` revertive impulses Aover, a fundamental circuit are employed under the control of counting relays, 'the number to be operatedbeing determinedfby the transla-` tor. Since theseoperations take place with in the calling oce they arethe same Jfor all classes .of distant oliices; `YVhere the called office also employs powecdriven switches, the further establishment of the connection iscontrolled byl revertive impulses andthe counting relays areY successively operatedV over one element of each numerical register of the sender. Where the distant oice is one employing: stepfby-step switches, the class switch will beso positioned as to transo fer the fundamental circuit from the control of the"counting relays to sequence switch type impulse transmitter. It likewise ren-4 ders a different clement oit each registeretfective to controla counting arrangement associated with the `interrupting ldevice This impulsetransmitting sequence switch has al plurality of normal positions andis o'peratedover the contacts ot a relay which when released permits the switch to `iassby a normalposition andwhen operate causes the switch to stop in the next norma-l position`` This -relay is operated over multiple connections to the registers. which are 1rem` dereldsuccessively etectite' to `close a shunt around 4the impulsingcontact when it has operated the proper number oftimes. The

circuit of this relay isaltered each time tha-tj Yswitch has two sets of brushes the impulsing sequence switch comes to rest in order that the multiple connections to the registers may appear in the same numerical order 'irrespective of the normal position from which the impulsing switch is started. When the impulsing switch 4comes to rest, a timing sequence switch is operated to measure a time interval during which the stepb -step switches huntI for an idle trunk. This timing sequence switch .causes the transfer of the control from register to register and prepares for the transmission of the next set of impulses. It is provided with a plurality of sets of contacts, any one of ,which sets may be employed so that the time interval may be varied at will.

The scope of the invention will be more clearly understood from a, consideration of the following detailed description and claims in connection with the accompany-` I is established from battery through the in drawings in which:

. ig. 1 shows a calling subscribers substation together with a diagrammatic showing` of a district selector and an otlice selector at the calling ottice and the necessary power driven switches and step-by-step switches for completing the connection to a subscriber in either type of office. A port-ion of a register sender is also shown;

Fig. 2 shows the control circuit'of a register sender including theA counting relays;

3 shows a class switch of the sender, and the relay call indicator impulser indicated by the dotted rectangle at the right side of the igure; c t

Fig. 4 shows the impulse transmitting seuence switch and timing switch embodying (fleatures of the invention;

Fig. 5 shows the code registers and register control switch of the sender; y

Fig.` 6 shows the translator and numerical registers of the sender; and

Fig. 7 shows the manner 1 and 6 are to be arranged.

The parts of the sender embodying the present invention have been disclosed in detail but only so much of the remaining parts have been shown as are believed necessary topan understanding thereof. A complete disclosure of a sender to which the present invention is applicable may be found in U. S. Patent 41.589,-102 to O. H. Kopp granted June 22, 1926. -This patent also discloses a district selector in detail and reference is made thereto for a complete disclosure of those portions of a system disclosed only fragmentarily herein. It may be noted that the\translator shown in Fig. 6

in which Figs.

in practice consists of two switches which,

are operated simultaneously' and that each and double terminal banks. Likewise it is customary to employ two sets of compensating resistances but since these features do not enter into the present invention they have been simi? ready to receive dial impulsesf plitied in the manner shown. The operation ot step-by-step switches is well known but reference may be made to U. S. Patent 1,231,013 granted to C. L. Goodrum June 26, 1917, for a detailed showing thereof.

Uall to power driven o/yce.

Assuming that the subscriber at substation 100 wishes to converse with the subscriber at substation 101 who is served by power driven machine switching apparatus and whose number is Booth 2579, he will remove his receiver from the switchliook and this operation will cause the association of his line with a district selector and a register sender in any desired manner, for example, as disclosed in the above mentioned patent to 0. H. Kopp. Switch 190 represents the link circuit of that disclosure. When the idle sender has'been selected a dialing circuit winding of relay 102, lilik 190, lower right and upper left contacts of Sequence switch cam 103, through line finder 104 to substation 100, back through the line finder 104, left contacts of cam 105 to ground throu li the right winding oi coil 106. The estailishment of this circuit causes the transmission of tone from coil 123 to the substation 100 to inform the subscriber that the sender Other circuits not shown are completed for holding the sender busy .and for connecting ground to the upper left contact of cani201 and thence to the winding vof sequence switch magnet 200.driving that sequence switch to position 2 in which position certain olf-normal circuits are closed. These operations, are fully described in the above mentioned patent to O. H. Ko p.

.The operation o vrelay'102 closes an obvious circuit for relay 107 which inturn closes a circuit for relay 108. When now the subscriber o crates his dial to transmit the .first letter o the oliice code, namely B, having a di 'tal equivalent of 2, relay 102 releases. bince relay 107 is Aslow to release it remains operated and a circuit is closed from ground over the back contact of relay 102, inner right front contactof relay 108, conductor 109, winding of relay 530, brush 501 ofregister control switch 500 in normal position, winding of stepping magnet 515, right back contact of relay 531 to battery. Relay 530 and magnet 515 operate in this circuit. The yoperation. of relayV 530 closes a circuit from ground over the left front contactofV relay 108, conductor 532, .front contact of relay 530, winding of magnet 506 to battery. agnet 506 'attracts its armature but since relay 530 is slow-to-release does not step the register control switch 500 until the digit has been completed. Magnet 515 in operating attracts its armature and at the completion of the first pulse releases it to step register 510 to its first off-normal posi-` tion. A branch ot the circuit of magnet 515 extends over theback contact ot that magnet, conductor 507, brush 502 innormal po-` sition, lett Contact otrelay` 531, conductor 111 to the wiiidingl of relay 110 and battery. This relay operates, connecting` ground to conductor r109 and to the winding of relay 107 until magnet 515 operates, to render the operation of the register magnet independ` entof the duration ofthe dial pulse. A similar circuit is closed over brush `5052 'for the setting of each register. The circuit ofrelay 10Q is interriu'ited twice and switch 510adyances to its `second ott-normal position.

Following the transmission of the rst digit relay 102 to permit relay 530 to release. Magnet 506 now retracts its armature to step the register control switch to its first ott-normal posit-ion. The pulsing circuit now extends `over theu rst off-norinal contact ot `brush 501, lett vback Contact of relay 533, Winding of mag- 535` outer right front contact of relay 108A to lator.

ground at the upper lett contact o'f'cam 203. Relay 534 closes a circuit troni battery through the windincr of translator operating magnet 647, hack contact ot magnet V646, to ground at the outer right frontcontact of relay 534; Relay `534 also closes va circuitA from grounded. conductor 535,` left contact of relay 534, brush 512 audits second olli` normal terminal, brush 523 and itssixth normal terminal;conductor 536to terminal 650 associated with brush 641 of the trans-l The translator is rotated" under the control of magnet 647 in' search of 4"this marked Contact. than brush`641 encouny ters terminal 650, the above traced circuit completed oyerbrush 641, conductor 651 to thel winding of relay 537 and battery' and in parallel therewith to the windingo'f magnet 6416 and batterjlr. Magnet 64:6 opens the circuit ofv magnet 647 and also applies a brake to bring tranlator switch 640`to rest in the position marked. Relay 537 closes a locking circuit tor relay 534 extending' from battery, winding ot relay 534 and its inner right front contact. contact of cam 204, outer lett contact ot relay 537 tonround. `Relay"y 537 locks over its inner right contact to ground at the outer right front contact ot relay 534. It closes a circuit from ground over its inner lett front contact, lower lett contact of cam 251, winding of sequence Switch magnet 250 remains operated long enough to battery to s advance this sequence switch `quence switch to position `3. It` furtherv closes a circuit from ground over its outer right front Contact brush 645, terminal 652, contact of cross-connecting rack 301, lower right `contact of cam 315, winding of class sequence switch magnet 300 to battery `to more sequenceswitch 300 to one of positions 7 or 18 in which positions the sender isprepared to control the establishment of a connection by means of power driven. switches.

At the same time, the numerical registers 600, 610,l 620 and 630 are being positioned and control switch 500` advanced in accordancelwith the dialing of the remaining digits. Thousands register 600 is set on its second oftnormal terminals, hundreds register 6 1() on its fifth, tens register 620 on its seventh, and units register 630 on its ninth of't'` normal terminals. sixth olf-normal position whenidialing is completed.

lith-sequence switch 200 in position 3 and sequence switch 250 in position Q a fundamental circuit is established for controlling'dist-rict brush selection. This cir-` cut may be traced in part from the upper `right contactot district selector sequence switch cam` 121, to Whichthe district relay is connected, over conductor `112, tbrough link 190. outer left normal Contact of relay 11.3, right back contact ot relay 114, right contact ot cam 205, right contacts of cam 252, 'winding of stepping: relay Q53.1 left `winding of relay 254, back Contact of relay 255,; resistance v206, lower Contact of cani 207 toground at the 'lower contact ot` cam Q56.

`Relay 253 operates in this circuit but relay 254 is polarized so as notto operate atthis time. The operation ot relay Q53 closes a circuit from lground-oyer theupper right contact of cam Q56, troni' Contact of relay 253. lower right contact of cam Q60,` right normal contact otrelay 352, right contact oie/cam 209, lower Contact ot cam 259, lower rightvcontact ot cam 258, brush 644 of the translator, conductor 257 back contact of the No. `1 counting relay, winding of the No. 1 counting relay, contact of cam 208 to battery. TheI No. 1 counting relay operates and locks through the winding ofthe4 No. 1 counting relay to ground at the lett contact of camA 274,' but the'No. 1 relay does not operate being shunted hy the operating circuit of theNo `1l relay. Stepping relay 253 is released in the well known manner by the adyance ot the district selector and relay Switch 500 stops in its i No. 1` operates to extend conductor `Q57 to*` the windinfr of the No. 0 counting" relay wliichds operati-df and loclred when relay Q53 reoperates.r The second release of relay 253 closed from battery, through winding of se-V left contact of cam 251.

permits the operation of relays 261 and 255 in the locking circuit ofthe No. 0 counting relay. r The operation of relay 255 opens the fundamental circuit to advance the district selector to position for group selection. The operation of relay 261 closes a circuit from ground over its front contact, lower right contact of cam 210, lower right contact of cam 251 to the winding of sequence switch magnet 250 and battery, advancing the sequence switch to position 4, and releasing` the operated counting relays.

In position 4 the Jfundamental circuit is established as before. A similar counting relay circuit is established this time over the left contact of cam 258 and brush 643.` Following the completion of group selection, quence switch 250 is advanced to position 6 in the same manner as itwas advanced to position 4. The districtselector is caused to hunt for an idle office selector and the district selector sequence switch then comes to rest in a position where the fundamental circuit is extended over the brushes of the district selector to the oitice selector.

A circuit is now established for testing the condition of the otlice selector which may be traced from the oflice selector over the tip brush of the'district selector, right contacts of cani 121 and thence, as previously traced, to the right contact of cam 205, through resistance 263, upper right contact of cam 264, winding of relay 265,.Winding of relay 253, left winding of relay 254, back contact of-relay 255, upper left contact ot' cam 266,lower left and upper right contacts of cam 211, conductor 212, brush 642, through a portion of compensating lresistance 648,l

conductor 649, contacts of cam 213, left back contact of relay 115, inner left -normal contact of relay 113, through the link 190, conductor 116, lower' left and upper right contacts of cam 122, ring brush of the district selector to ground in the office selector. If the otlice selector is ready to make selections, relay 265 operates, in turn operating relay 267. lVhen relay 267 operates a circuit is quence switch magnet` 250, over the lower lett contact of cam 262, lett front contactof relay 267 to ground at the lower left contact of cam 203. Sequence switch 250 is advanced to position 7 and immediately out of position 7 to position 8 over the upper In position 8 the fundamental circuit for oiiice brush selection is closed. This extends as traced for office test with the exception that a shunt is closed over the right contacts of cam 252 around resistance 263 and relay 265. The countingr relay circuits for this selection and otlice group selection extend through brushes of the translator but these have not been shown.

` Sequence switch 250 is advanced to position 10 following ottice brush selection and to V254. It will be noted that position 12 following oice group selection.

In position 12 the trunk extending to the incoming selector is tested over the same circuit in the sender afs that to the otiice selector. Sequence switch 250 is advanced to position 14 if the setector is ready. The fundamental circuit in position 14 is the same as previously traced except that it extends to battery and ground in the incoming selector. The counting relay circuit extends, as previously traced, to the lower left contact of cam 259, and thence over the upper right contact of cam 259, left normal contact of relay 350, brush 602 of the thousands register 600 in its second ott-normal position, conductor 257 to the back contact of the No. 1 counting relay, winding of the No. 1' counting relay to battery at the contact of cam 208.` Incoming brush selection now takes place after which sequence -switch `250 is-advanced to position 16. The fundamental circuit for incoming group selection is the same as traced, the counting relay circuit extending at this time over the left contacts of cam 259, brush 601 of the thousands register in position 2, left front contact of relay 653 (which is operated since register 610 is in position 5) to the winding of the No. 3 counting relay. At the completion of this selection sequence switch 250 is advanced to position 18.

With switch 250 in position 18 a circuit is closed from battery through the winding of sequence switch magnet 200, upper right contact of cam 201, contacts of cam 270, right contact of cam 304 to ground, advancing sequence switch 200 `to position 4. The fundamental circuit now extends over the lower left contact of cam 205, lower contacts of cam 252. tothe windings of relay 253 and relay 254, back contactof relay 255, upper right contact of cam 266, lower right and upper left contacts of cam 211, conductor 212 and thence as previously traced. In practice the circuit would hearranged so that a .different compensating resistance. might be used for these selections. Final brush selection takes place with sequence switch 250 in position 18, final tens selection in position 2 and final units selection in position 4 in the manner described, the counting relay circuit being completed over contacts of cam 277 and brushes 612, 622 and 632 respectively.

lVhen the selections are completed sequence switch 250 is advanced to position 6 and a circuit is closed for relays 253 and since switch 200 is in position 4 the circuit which formerly extended to relay 265 in position 6 is not closed. `Then selections have been completed the incoming selector reverses the connection of battery to the fundamental circuitin the well known manner, causing the operation of polarized relay 254. This re-` lay locks in a circuit `from battery through its right winding, contact` of cam 271 to ground at its right front contact. In` con- ]unction with. relay 253 it closes a clrcuit for the No. 0 counting relay. The incoming selector removes.battery` aiter a brieinter val so `that 'relay 253 releases to cause re. lays and 261 to operate.l The opfer-ation of relay 261,"advances sequence switch 250 from position 6 whence it advances to posi-l tion 8. Relay 254 releasesduring this advance. 1 t i Since relay 254 was operated at the time,

the operation of relay 261'also closed a circuit from ground at its front contact, lower left contact of 1ca1n210, outer left contact of relay 254, to the windings` of relays 114; and 115in parallel. These relays operate, opening the fundamental circuit' and causing the advance vof the district selector `to. 'ai position in which it is ready for makingV talking selection. In addition the operation of relay y114 closes a` locking circuit for relays 114 andk115 over its left front contact to ground at the upper contact of cam 214.

Relay 115 in operating closes la circuit `from,

ground over its outer right front contact,

left contacto cam 215, winding of se-` quence switch magnet 200 to battery, :id-j

vancing the sequencefswitch to position 5. The advance of the district selector opens leases relays 107 andl108. With` relay 107 released a circuit is closed `fromground at its normal contactover conductor 539, brush 505, and its sixth, seventh" and,` ,eighth offnormal terminals, back contact and winding of magnet 506 to battery.1` Switch 500" is advanced to its` ninth off-normal position in this circuit. `Vhen switch L500 arrives in this position the circuit for making talking selection is completed extending from the district selector over conductor 112, outer left normal contact of relay 113,right front contact of relay 114., upper left and lower right contacts of cam 252, winding of re`- lay 253, lett winding of relay 254, back con tact of relay255, resistance 206, upper contact of cam 207, ninth `terminal of brush `505, conductor 539 to `ground `at the normal contact of relay 107 `The counting relay circuit for this p selection is also completed through the translator but is not shown.

Following the selectiomthe operationof re-` lay 261 advances sequence switch 200 to poe sition 6. As soon as the switch reaches po` sition 6, circuit is closed from battery, through the winding of magnet 250, the upper left contact of cam 251, lower right contact of cani 203 to` ground to advance sequence switch `250 to positionl. Sequence switch 200is then also advanced toposition 7 which is' also a normal position, over' a circuit which extendszover anormal Contact of the relay call indicatori-impulser switch,

left contact of cam 304 to ground. y cuit is maintained `until sequence switch 250 reaches position9 on itssecond revolution; With relay 350 operated and` switch 300 in. position 4` lthe counting relay `circuits. are` @all to step-by-step n office.

"If thesubscriber `atsubstation 100 wishes tok converse with the subscriber at substa- `tion 191 located in the step-by-step` oiiice whose number.' may be assumed to be `IN-` `wood 2579he will dial the number ofthat subscriber in the same manner as for any other oflice.` Register 510 will be positioned on itsv fourth oit-normal terminals and switch 520 `on its sixth. The operation of relay 534L extends ground from conductor 535,0ver its left front contact, brushV 512 4and its fourth terminal, brush 522 and its` sixth terminal to terminal 655 associated with brush 641. Translator 640 therefore comes to restl in the corresponding position. `The operation ot relay537 closes a circuit from ground overV its outer hight t'ront contact, brush 645, contact 654, cross-connecting rack 301, lower lett contact of cam 302,

winding of `classsealuence switch magnet 300 to battery. Class switch 300 therefore is moved to position 4 to control the establishment of the connection over step-by-step Y switches. The. fdistrict and oiliceselections are made as betere except that atrunk 1s selected extending to the step-by-step olice. y `When sequence switch 250 reaches `position thecircuit for relay 102 which in turn re- 101A?, following district and office selections,

parallel circuits extending from battery through their windings, rightback contacts of relay 118, contacts of cams 275 and 216, This cir-` opened, whilethe circuits which render the registers lsuccessively effective are transferred from brushes 602, 612, 622 and 632 to brushes 603, 613,623 and 633, respective#` ly, and `from controlling the relay callindicator impulse switch tocontrolling the` step-by-step impulse switch. Relays 351 an 352 restore the` multiple connections from the thousands register to the same numerical order-as the other registers, the relay call indicator code for this di it differing fromthat orthe hundreds igit, etc. Relay 352 also transfers the circuit controlled by the registers from the contact of the stepping relay 253 to ground. Relay 353 opens certain connections to the relay call indicator impulse switch. Otherwise the selection of an outgoing trunk and the advance of sequence switch250 to position 12 is the same as previously described.

Vith switch250 in position 12 and switch 200 in positon 3 the fundamental circuit includinor relay 265 is reestablished extending from batteryY through the i upper winding` lio of relay 161,7side switch arm 162 in position 1, terminal 163, tip brushes of the oliice selec-tor and district selector, right contacts ci' cam 121, conductor112, through the link 190, outer left normal contact ot' relay 113, right back contact of relay 114, right Contact of cam-205, upper contact of m1111303, lower right contact of cam 264, winding of relay 265, winding of relay 253, left winding of relay 254, back contact of relay 255, lowercontact of cam 266, conductor 212, brush 642, compensating resistance 648, conductor 649, contacts of cam 213, left'back cont-act of relay 115, inner left normal contact of relay 113, through the link 190, conductor 116, lower left and upper right contacts ol cam 122, ring brushes of the district selector and `ollice selector, terminal 164, side switch arm` 165, in position 1, =lower windingl of relay 161 to ground.- It will be notedv that resistance 263 is shunted at this time.`

Relays 161 and 265 both operate in this circuit. c Relay 161 closes an obvious circuit for relay 166 which prepares the operating circuit of the first selector. Relay 265 operates relay 267 in the usual manner, advancing sequence switch 250 to position 14. Relays 161 and265 are maintained operated in position 14 by means of a circuit which extends as traced to the upper contact of cani 303 and thence over the right front contact-of relay 267, left cont-act of camk 264, to the winding of relay 265. In position 14 a circuit is closed from battery through the winding of relay 113, righteoutacts of cam 305, conductor 309, contacts-of cam 273, right contact `of cam 274 to ground. Relay 113 loclrsy over its inner` left front contact, outer left back contact of relay 118, right oontactot' cam 275,1'ight contact of cani 216 ,to groundatthe left Contact of cam 304. Relay 113 in operating extends the circuit of relay161 by means of its make-before-break contacts to the impulser sequence switch 400. the circuit now extending from battery throughV the upper winding vof relay 161 and thence as traced to the outer left alternate contact of relay 113,conductor 117 lower contact of cam 401, back contact of relay 403, conductor 402, inner left alternate contact of relay 113 andback to ground through the lower winding of relay161. The circuit vof the relay 161 is therefore maintained during these changes at the sender.

The operation of relay 113 also initiates the transmisisonof pulses for operating the rst selector by closingr a circuit trom battery lthrough the. -winding of sequence switch magnet 400, left contact of cam 405, right back contact of relay 404, lower right Contact of cam 451, conductor 452, outer right front contactof relay 113, inner lett contact of relay 118, contact of cam 276 to ground. Sequence switch 1400 will Vbe moved rfrom its normal position 1 by this circuit. The pulsing circuit above described is maintained until Vswitch 400` leaves position 1% over the lower contact of cam 401. In position'l/g it is Vmaintained over the upper contact of cam 401. The cam contacts having a tixed width, these circuits overlap and the pulsing circuit is not opened until switch 400 leaves position 1%. With both contacts of cam 401 opened, which occurs as soon as t-he switch leaves position 1%, the circuit of relay 161 is opened and that relay falls back to advance the iirst selector through one ver'- tical step. In position 1% a circuit is closed from battery through' the winding of relay 403, upper contact of cam 406, conductor 407, lower right and upper yleft contacts of cam 306, upper left contact of cam 203 to ground. Relay 403 locks over its right 'front contact, left back contact of relay 404 to grounded conductor 40T. As switch 400 passes through position 23/8 the upper contact of cam 401 is again closed and relay 161 reoperates. `When the switch' leaves position 2% the pulsing circuit is opened a second time and relay 161 falls back to advance the first selector a second step. When sequence switch 400 reaches position 3% the upper contact is again closed, and relay 161 again operates. As soon as switch 400 reaches position 31/2 a circuit is closed from battery through the winding of relay 4,04, the left back contact of relay 412, outer left back contacts of relays 411 and 410,' lower right contact of cam 420, conductor 442,` the innerright front cont-act of relay' 352, second OI-normal terminal of thousands register brush 603, left contacts of cam 310, outer left alternate contact of relay 350, upper right and lower left contacts of cam-259, right Contact of cam 209, outer right front contact of relay 352 to ground. Relay 404 operates in' this circuit lockingover' its inner right contact, lower right contact of cam 453 to grounded conductor 407. Relay 404 in operating connects conductors 117 and 402 to her over its outer right front contact lndependent of the contacts of cam 401', thus preventing the transmission of anymore impulses. In addition it opens the locking circuit of relay 403 permitting this relay to release as soon as switch 400 reaches position 4. It also opens at its left back contact the operating circuit for magnet 400 so that this magnet comes to rest in its next normal position, namely, position 4.

The operation of relay 404 also initiates the operation of timing switch 450 to provide a time interval in which the first selector may hunt` for an idle trunk, by closing a circuit from battery through the winding of relay 456, right back contact of relay 457, lower right contact of cam 458, inner las left? front contact ot `relay" k404ito grounded` conductor 407. Relay 456 closes an obvious` circuit for relay 457 andilocks `over its in ner right front contact to grounded conduc-V tor 452.* Relay 457 "in operating closes a circuit troni batterythrough the winding of sequence switch inagnet 450, lower` right contact of cani 459, iniiei` left front contact oi relay 457' to ground, advancing `sequence switch 450 troni position 1. With sequence switch 450 .in position 2 a circuit. is closed troni battery through the winding and nori uial contact of relay 410, upper contact oi"y right contact of cani 460. fRelay 456 in operating alsocloses a `circuit from ground atits vleft .frontzcontach lower contacts of cani 311, upper `right contact of cani 262,`

winding of magnet 250 to battery, advancindividual locking circuit extending over its right front contacts and right bay-ck contacts ing sequence switch 250 to position 18 pass ingdirectly through position 16 in which incoming group selection was made under the jointcontrol of theithousands and hundreds registers in` extending thepreviously traced call.,` As switch 250 leaves position 1.7 the locking circuit of relay 456 is` opened and thatfrelay releases in turn opening the f circuit of relay 457.y When relay `4561eleases the operating circuit of magnet 250 is opened thus insuring that sequence switch 250 will not be driven beyond position 18. Vith sequence switch 250A in position 18, sequence switch 200 is advanced to position 4 as previously described. Relay 457 has an oi? relays 410, 411 and 412 to the lower contact` ot Acani 413 which is `maintained until one ot, these relays is operated. Since switch 400 carne to rest in position4, relay 410 operated as soon as switch 4501noved troni position 1 so that relay 457 is released at this time. Vith both relays 4564 and 45,7 released, a circuit is closed from Vbattery throughthe winding of niagnet 450, lower right contaetof cani455, left back-contacts ot relays 450 and 457 to ground at the upper right contact ot' cani 413.'` Sequence` switch 450 is advanced to position 4 in this circuit.

` As switch 450 passes troni position 3 to position 4 the locking circuit of relay 404 is opened andthat relay releases.` However, with relay 403 released the shunt around the pulsing contact of cairr 401 is maintained closed. y When relay 404 closes its back contact sequence switch 400 is advanced from position 4 over the circuit traced .inposition 1. As it passes from position 43/8 the cirreleasingr relay y 412. periorxns notrunk `hunting operation, the

cuit` *of the pulsing relay of" the second sie-` lectorisfopened to advance that selector one verticalstep. Relay 403 operates as soon as switch `400 reaches position 4%. Since hundreds register 010 isin vposition 5, con ductor-445 is grounded, the circuit extending i'roi'n brush 613 over the lower left and upper right contacts ot'` cani 312, inner right Yfrontcontact of relay `350,` upper right and lower lelt contactsoif cani 277, lett contact otcanr209, to grou-nd at the outer right con` tact `otrelay.352. `Since relay 410 is operi ated'tlie circuit 'troni conductor 445 over the lower left contact of cani 421 is open `and .relay 404 is not `operated in position til/2. "llierelore when switch 400 reaches osition` 7 its start-circuit remains closed an itcontinues to advance troin position 7. Then it` reaches position `91/2 the grounded conductor 445 is extended over the lower left contact of cain 424, outernleft front `contact oi"` relay 410, `outer lett back contacts of relays 4 11` and 412 to the `winding of relay 404.

Relay 404 perfor-ins the saine functions as previously described so that only impulses aresent `out and switch 400 coinestoj rest in position 10. `Relays 456 and 457 are operated, lrelay 456 advancing sequence switch 250 "from position -18 to position 2,"andrelay 451` advancingythe.sequenceswitch 450 troni position 4.` Switch ,450 is carried through position-5 as it `was carriedthrough pt )sition` H2. `lfVhen sequence ,switch 450 leavesposition 4, the locking circuit of relay 410 isopened and that relay releases.. With sequence `switch 400 Ain position 10, and. switch `450 in position `5, relay `412is operated over the loweri'ight contact of ca1n409.

Relays 45Gand 457 are `released as before, and switch 450 is advanced to position 7.

lThe cycle ot operations.. above described is nowrepeated to cause the transmission of 'seven impulses to direct the connector switch toiits seventh. level. Register 620 being in position 7, ground` is connected to conductor 447, over brush 623, lower lei't and upper right contacts 03Ev cani 313, inner lett front con tact of relay 350,` lower contacts of cani 277, left contact of 'cani `209 4to ground at the outer right contact of relay` 352.` With relay 412 operated `the multiple connections troni conductor 447 over canis 421, 424and 427 are opened. Then sequence switch 400 vreaches position 171/2, conductor 447 is extended over the upper right contact of cani 430, inner left back contact of relay 410, in* ner left contact of relay 411, left Jfront contact of relax 412 tothe windingoic relay 404, to stop thetransinission of pulses and to vbringsequence switch 400 to rest in position 1.` Sequence 450 is advanced` from position 7 to position 8 bythe operation ol relay 404, Since the connector time interval need be only long enough to transfer' from vertical to rotary operation. Therefore switch 450 is moved through no intermediate positions, but. relays 457 and 456 are operated at once in position 8. Relay 456 advances sequence switch 250 to position 4. Since sequence switch 400 came to rest` in position 1,\none of the relays 410, 411 or 412 aie operated, but no locking circuit is provided for relay 457 with switch 400 in position 1, therefore relay 457 releases when relay 456 releases due to the advance of sequence switch 250. The release of these relays advances switch 450'to position 9 in which position it causes the reoperation of sequence switch 400 to transmit impulses to cause the connector to advance to the terminals ot the wanted line. With units register 630 in position 9, conductor 449 is grounded over brush 633, lower left and upper right contacts of cam 314, `outer alternate contact of relay 350, left contacts of cam 277, left contact of cam 209 and the outer right alternate contact of relay 352. Since none of the relays 410, 411 or 412 is operated, the multiple connection of conductor 449 to the lower contact of cam 422 is effective to operate relay 404 following'the transmission of nine impulses, arresting se quence switch 400 in position 13'. As before, relay 404 causes the operation of relays 456 and 457. Relay 456 advances sequence switch 250 to position 6 and relay 457 advances sequence switch 450 to position 10. A locking circuit for relay 404 is closed over the right front contact Aof that relay, lower contact ot' cam 406 to grounded conductor 407 until switch 400 leaves position 121/2, but no locking circuit is closed over cam 453. Therefore, relay 404 is released when switch 400 comes to rest in position 13. However,

since switch 450 is in position 10 the operating circuit of magnet 400 is open atcam.

451 and the sequence switch remains at rest. The pulsing circuit remains closed over the lower contact of cam 401 and the back con tact of relay 403. f

lith sequence switch 450 in position 10, a circuit is closed from'battery through the windings of relays 114' and 115 in parallel,

lower left and upper right contacts of cam 268, conductor 278, lower right contact of cam 462 to ground. Relay 114 closes the same locking circuit for itself and relay 115 as whenoperated in the previous case. Rela 115 causes the advance of sequence switc 200 to position 5 as previously described. It also serves to advance sequence switch 250 to position 8 over the lower righbcontact of cam 262. in place of the reversal of battery supplied by the power drivenincoming selector. As before, the operation of these relays causes the district selector to advancel to position for talking selection, at which time the connector is held `from the district selector.

right' The advance of thedistrict releases relays 102, 107111111 108, causing register control switch500 to advance to its ninth off-normal lay .108 to ground atthe upper right contactl o1" cam 203. This relay opens the holding circuit of relay 113 Vrestoring the fundamental circuit. Therelease ot relay 108 also closes a circuit from ground at its left normal contact, conductor 463, upper contact ot cam 464,` winding of sequence switch magnet 450 to battery advancing this sequence switch to position 1. W' hen sequence switch 450 reaches position 1, conductor 463 is extended over the lower contact of cam 464, right contact of `cum 405, winding of sequence switch magnet 400 to battery, advancing sequence switch 400 to position 1.

As soon as the fundamental circuit is restored, talking selection takes place, and sequence switch 200 is advanced to position 6.

With sequence switch 200 in position 6, sequence switch 250 is moved to position 1 and the sender restored to normal as before.-

As a further illustration of the manner in which the pulsing sequence switch1400 operates, assume that the wanted number is 5525. The sequence switch 400 will be started from position 1 as previously described. Since the `tiret digit is 5, conductor 445 will be grounded from brush 603 of the thousands register. Pulses willbe sent out from cam 401 as described in passing from positions 1%, 2%, 3%, 4% and 53/8. 1n position 61/2 grounded conductor 445 will be connected over the lower left contact of cam 421 and the back contacts of relays 410, 411 and 412 to the winding of relay 404 which in operating shunts the pulsing contact 401 and performs the other functions heretofore described in detail. bringing switch 400 to rest in position 7. The advance of the timing sequence switch 450 closes a circuit from battery through the winding and normal contact of relay 411, lower right contact ol cam 409, lower contact of cam 454, left front contact of relay 404. to grounded conductor 407, relay 411 locking over the lower right contact of cam 461 to grounded conductor 407. I

lVhen switch 400 again starts'to rotate conductor 445 4is again grounded,` this time from brush 613 of the hundreds register. lVith relay 411 operated the multiple connection of conductor 445 over cam 421 which was ,formffrly effective is open as is also that over cani 424. Sequence switch 400 theretore continues to rotate until it reaches position 121/2 having caused the transmission of 5 impulses. In position 12% conductor 445 is connected over the .lower left' contact of cani 427, outer left front contact` of relay 411, back contact of relay 412 tothe winding `of relay 404. `Vith relay `404 `operated switch 400 stops in position 13.` Switch 450 is now again operated releasing relay 411 andk closing circuits `from battery through the winding and .normal contact of relay 410.0verptl1e uppercani of Contact 409 and from battery through the winding and normal contact of relay 412, over theleft contact of cam 409, and thence as previously traced to grounded conductor 407 to ywhich both relays lock.` Y y i After the .measured time interval, switch 400 is advanced from position `13. `Tens register 620 is now effective to ground .conductor 442 over brush 623. Conductor 442 is connectedin multiple to the lower right contacts of cams 420, 423-426, 429, 432, and 495. Vith both relays 410 and 412 operated it will'be seenthat the only oneof these connections `which is effective is that over cani 432. After two pulses have been4 sent out switch 400 reaches position 151/2 and re lay 404 is operated over cani 432.` Switch 400 is then brought torest `in position 16. The advance Vof `timing switch 450 releases relay/S410 and 412 but in the nextiposition ofthat switch relays 411 and 412 areoper# ated over thelower contact-s of cani 409.

Units register 630 is effective on the next advance ofsequence switch 400 to ground conductor 445. `With relays 411 and 412 operated only the multiple `connection from conductor 445 to the lower left contact of cani 436 is effective. As sequence' switch 400 passes through positions` 16%, 17 378, 18%, 13/8 and 23/8, five pulses are sent out from camr401. `In position d1/3 relay 404 is operated and the transmission of pulses ceases, switch 400 stoppingl in position 4. It, is believed that this drliscription in vconnection with the more complete description previously givenr will clearly indicate how the inul tiple connections from the registers` become effective in the` same numerical order, irre spectiveof the normal positiorrfrom which sequence switch 400advances. j i

The function of `sequence switch 450 as above indicatedisito introduce a time interval between series ofimpulses during which the step-by-step switches `may perform' their trunk hunting operation. In orderthat this time interval may be adjustable inl accordance with the needs of the oiiice` in which thesender of the invention is being install-ed, a, plurality of sets` of circuits have been provided.y The circuits performing the same functionsv are terminated on cross-connecting racks and are solai-ranged that when the incoming conductors are connected to the contacts occupyingr the saine relative position on the corresponding` racks they `will eooperate to function as described above, in

"which Ycase the lowerrnost contact on `each selector` and from position 5 to position 9 during the trunk hunting operation of the` secondv selector. In the case of the third contacts switch 450 would, be moved from posit-ion 1 to position `7 during trunk hunting by `the first selector and in the case of the fourth or top contacts,`from position 1 to position 9 at this time. Similar intervals areprovided for the second selector While the same interval is allowed for the transfer from vertical selection to rotary selection by the connector switch in each case.

faZZ to operator. g q This sender is also provided with means whereby a special "four `digit code may be used for makingcalls to operators, etc., permitting a` greater variety of such callsthan is provided bythe usual 1-1-X or X--l--l type ofncode.` The codeswhich may be ein-` ployed in connection `with the present arrangement lie between1001 and 1019, inclusive. When -register 510 is advanced one step. inV response `to the dialing of the digit 1, and relay 530 releases, a circuit- `is closed Y from battery throughthe left windingof relay 531first off-normal terminal of brush 511, contact-s of cam 217, normal contactA of relay 530, 4conductor 532 to ground at the innerj left `front contact of relay 10,8. Magnet 506 of the register control switch 500 is held operated in a circuit from battery through the winding of the magnet, brush 513 in itsfirst off-normal position, conductor 535, outer right front `contact of relay 108, toground at the upper contactof can1203. Thus magnet-.506 cannot-release to advance the `registercontrolswitch to its first 'offnornial'positi'on. lelay 531 opens the operating-circuit of magnet 515 and also closes a holding 1circuit. `for itself from battery through its yright winding and inner right front contact, normal contact of brush 501, t-o the winding ofc-clay` 530. 530 is operated in response to the dialing eri lll)

When relay i of the nextdigit, the `operating circuit of relay 531is. opened. `Since relay 102 attracts its armature following the first impulse, the holdingcircuit of relay 531 is also opened so that'it restores the kcircuit of rnag-` net 515and the remainingdigits are received on register 510.` Since the second digit is 0, a circuit is closed when register 510 comes to restfrom battery through the winding of relay 533, brush 511 in posit-ion 10, contacts of carn217, no1-mal contact of relay 530, conductor 532 to ground at the left front contact of relay 108. Relay 533 extends its operating circuit over its inner right front contact, terminal 10pt brush 513 to the windof the units numerical register. It likewise transfers the circuitof relay 110 'from'the reventing the re# tiek' Comici of ringnet` 525 to lthe back con'- tact of magnet 634.' When the next digit is receved, t'is registered onthe second y,half oft ye 'register 510; This digit will be entier zer'o or' 1, neither one of which isemp'loyed in the usual ,olfiice Code, so that terminals 11 and 20' 'associited with brush 512 1re connected to brush 63,1 of register 630. Following this digit magnet 506 isl permitted to release to advance switch 500. Due to the operated condition `of relay `533, Ithe 4th digit is' registered on the units register 630,'and the coinbined setting of register 510 and r`egist'er is employed to 'set` the translator. it will he observed that the digit l was absorbed in ythe iisl manner. The manner of employing the second half of the 4first fc`ode register has been employed heretofore, Ato afford'an opportunity for enlargingthe number of office codes, as described and claimed in U. SQPatent 1,595,072 granted August 10, 19%. to C.Caver`ly.

vliVhat is claimed is 1. In a telephone exchange system, a switch controlling mechanism comti'r'ising registers having a pluralitywof elements,

mais for controlling th 'seeing of switches of one type'by impiilses yreceived from said switches during 'the settingthereofl u'nderthe oooltrol of oortoio olmenfs. of Sad registers, means for controlling the setting of switches of. 'another typo by" transmitting intiuls. thereto nnderthe control off other eleme ts of said,y registers, means dependent uponl the iiice designation of a call for selecting either of said switch controlling means` and'ineans controlled by'said last meanstoselect the proper elements of said registers. 2. In a/telephone exchnge system. a `svvitch controlling mechanisni lcomprising registers having a plurality of brushes and terminal banks. means for controlling the settingr of switches of one type by impulses receiiied from said switches during` the set-` ting thereofv under the control` of certain brushes and terminals of ',sfaid registers, means for controlling the setting ofswtches of another type by transmitting impulses thereto under the control of other brushes and terminals of said registers, means dependent upon the office designation oa. call for selectingeither of'said switch control# ling ineens. and meansv controlled by said lnstrnean's to select the properbrushes andi terminals of said registers.

' 3. In a ytelephone exchange system. n switch controlling mechanism, means for controlling the setting df switches of one type i received from said switches during t e setting thereof, means. for con;` trolling the setting of switehesof another type by transmitting impulses thereto, separate means f or determining the nnmber of impulses 'for-the ysettin of each type of switch and'xnens oper ed in accordance with Resignation of s @auf to select the proper nu'mher determining means.

A4. In at'elephone system, a switch centrolling' vrnechtznism comprising registers havln 'a plurality of elements `means for contro ling the setting of switches of one typeby impulses ieceived ufrom said switches during the setting thereof under `the control of certain elements of sftid registers and a number determining means, means for controlling the setting of swithes of 'another type by transmitting impulses thereto under the control of other elements of sind regis ters determinino and viuiother number Y meana'm'eans operated iii'v accordance witi the oillce designation of a-cll for selecting one'of said number determining means and means controlled by said lust mentioned means to associate the proper elements of said register with said eogiltrolling means.

5. Ina telephone systemyselectdrswitche's having directive and trunk hunting move'- ments, a switch controlli mechanism comprising a plurality of sters, an impulse transmitter, means for repeatedly operating said transmitter to tran'srit 4series of selec# tor directive impulses underfcontrol of` said registers, a timing switch, means to operate said switchto introduce a'irnsuredf inten-val between successiveroperatisof said'imp'ul'se transmitter for permitting thev trunk hunting movements ofsaid selector switches, and means for atvvill varying the interval so measured. n Y

6. In a telephone system, selector switches having directive and trunk hunting movements, a. switch controlling mechanism comprising :1 plurality of regxstexs, an impulse transmitter, means for repeatedly operating Said transmitter 'to transmit series: of selector directive impulses und'r controlfofsaid` registers, a timing switch havinga plurality of' positionsof rest, means to advance said l switch between said pos'ions of rest yto int-rod'uce a measured inteirvqlbetween successive operations of said transmit-- ter for permittingfthe trunk hx'lnting'move'-V men'ts of selector swiwhea, and means for at will varyingthe positions of rest to vary the intervals so measured.

7 In a't/elephone system, sehotor switches having directive and. trunk hunting.y mosements, a 'switch controlling'mechanisin. comF prising a pluralityof regiuens, anA impulse transmitter, means 'for repetedly opemtnng said transmitter toA transmit serres of selector directive impulses undtotrol o'said:

sive operations of said impulse transmitter for permitting the trunk` hunting movements of said selector switches, and means for at will rendering other positions of said switch positions ofrest to vary the intervals so measured. v

S. In a telephone system, selector switches I having directive and trunk hunting movements, a` switch controlling mechanism `comprising a plurality ot register, an impulse transn'iitter, means for repeatedly operating said transmitter to transmit series of selectorl directive impulses under eontrolof saidreg-` isters, a multi-position switch, `circuits associated with said switch whereby certain positions ,of said switch are positions of rest,

means to advance said switch between said positions of rest to introduce a measured interval between successive operations of said impulse transmitter for permitting the trunk hunting movements of said selector switches, and means `for `varying the inte-rvals `someasured comprising means for at will varying the association of said circuits with said switch to render other positions of said switch positions of rest. i

9. In a `telephone system, an impulse transmitter having a plurality of normal positions, means for countingthe number of impulses transmitted .and means to move said impulse transmitter to one of said nor-` mal positions in accordance with vthe number of impulses transmitted.

10. In a telephone system, an impulse transmitter having a plurality of normal positions separated by transmitting positions, said transmitting positions being less `in number than the maximum number of impulses to betransmitted, means tor counting the number of impulses transmitted and means to move said impulse transmitter to one of said normal positions in accordance with the number of impulses transmitted.

11. In a telephone system, an impulse transmitter having a plurality of normal positions, means for determining' the number of impulses `to be transmitted, means for arresting said transmitter in anormal position after a predetermined number of impulses have been transmitted, a plurality of conductorseonnecting said number determining means and said arresting means, and means for rendering only one ot said conductors effective at any one time.

1Q. In a telephone system,` an ,impulse transmitter having a plurality of normal positions, a register for determining the number of impulses tobetransmitted, means for arresting said transmitter in a normal position after a predetermined number kof impulses `have been transmitted, a plurality of conductors connecting `each positionof said register with said arrestingmeans and means for rendering only Vone otsaid conductors `effective atany one time.

V13. Inra telephone system, a switch controlling mechanism comprising a plurality of registers, an impulse transmitting switch having a plurality of normal positions, multiple connections extending from the terminal banks of said registers, a plurality of conductors connecting each ,multiple connection with said transmitting switch and means to render onlyone of saidctmductors effective at atime. i i

14. Ina telephone system, a switchcontrolling mechanism comprising a plurality ot' registers, an impulse transn'iitting` switch having a plurality of normal positions, multiple connections extending from the terminal banks yot said registers, a plurality of conductors connecting each multiple connection with said transmitting switch` and means for rendering oneof said conductors eifectivein accordance with the normal position from which said switch` is moved.

15. `In a telephone system, a vswitch controlling mechanism comprising a plurality of registers, an impulse `transmittingswitch having a plurality of normal positions, multiple connections extending from the terminal banks of said registers, a plurality of conductors connecting each multiple con nection with said transmitting switch, and i means for rendering one of said'conductors effective in accordance with the position of the register and the normalposition from which said switch is moved. y

16. In a telephone system, an impulse transmitter having a plurality of normal positions, means for detern'iining the number of impulses to be transmitted, means for starting said impulse "transmitter from any normal positioinineans for arrestinU said transmitter in a. normal posit' )n ater a predetermined number of impulses have been transmitted, a plurality of conductors connectiiw said number determining means and said arresting means, and i'neans `for rendering said conductors ei'ective in accordance with the normal position from which said switch. is started. y i y 17. In a telephone` system, a switch controlling mechanism comprising a `plurality of registers, an impulse transmittingswitch having a plurality of normal positions, multiple connections extending from said registers to said impulse `transmitting switch, and means whereby said switch is enabled to pick up said multiple connections in the same numerical order regardless of the normal. position from which said `switch is moved.

18. In a telephone system, a switch concontrolling mechanism comprising `a plulio` rality of registers, an impulse transmitting switch having a plurality of normal positions, multiple connections extending from terminal banks of said registers to said imulse transmitting switch, and means wherey said switch is enabled to pick up said multiple connections inv the same numerical order regardless of the normal position from which said switch is moved.

19. In a telephone system, a switch controlling mechanism comprising a plurality of registers. an impulse transmitting switch having a plurality of normal positions, multiple' connections extending from terminal banks of said registers to said impulse trans` mitting switch., means to repeatedly operate said impulse transn'iittingl switch, means succes'fivclyv controlleril by said registers to stop the transmission of said impulses and to arrest said switch in a subsequent normal position, and means to associate said multiple terminals with said switch in the samenumerical order regardless of the normal position from `which said switch is moved.y

20. In a telephone system, a switch con-y trolling mechanism comprising a plurality of registers, an impulse transmitting switch having a plurality of normal positions'sepnratedby impulse transmitting positions less in number than the4 maximum number ofimpulses to be transmitted, multiple connections extending from terminal banks of said registers to said impulse traimitting switch, and meansr whereby said switch is enabled to piek up said multiple connections in the same numerical order regardless of the n'ormal position from which' said switch is moved. Y

21. Ina telephone System, a switch controlling mechanism comprising `a plurality oi registers, an impulse transmitting Switch having a plurality ot normal positions separated by impulse transmitting positions less in number than `the maximum number of impulses to be transmitted, multiple connections extending;r `from terminal banks of said registers to said impulse transmitting switch, means to repeatedly7 operate said impulse tran'smittin switch; means successively controlled said registers to stop the transmission ot said impulses and to arrest said switch in a subsequent'normal position, and means to associate said multiple terminals with said switch in the same numerical order regardless of the normal position from which said switch is moved.

In witness whereof, I hereunto subscribe my name this 24th day of March A. D., 1927.

GEORGE THoMPsoN. 

